   [barrel-radius pixel bomb]
   (do
     #_(log/warn pixel bomb)
-    (let [delta (distance barrel-radius (:center bomb) (:barrel pixel))
-          radius (* (:age bomb) 0.00003)]
+    (let [speed (:speed bomb)
+          delta (distance barrel-radius (:center bomb) (:barrel pixel))
+          radius (* (:age bomb) speed)]
       (if (<= delta radius)
         (color/rainbow (/ delta radius))
         color/none))))

      [:time/tick nil]
      (let [elapsed (or (:elapsed event) 0.0)]
        (assoc this :bombs
          (map (fn [bomb]
                 (let [age' (+ (:age bomb) elapsed)]
                   (assoc bomb :age age')))
               (filter #(< (:age %) 10000) bombs))))

      [:axis/direction :y-axis]
      (assoc-in this [:cursor-position :z]

    [this pixel]
    (do
      #_(log/warn pixel bombs)
      (let [bomb-colors (mapv (partial bomb-color barrel-radius pixel) bombs)
            cursor-delta (distance barrel-radius (:barrel pixel) cursor-position)
            cursor-color (if (< cursor-delta 0.04) (color/gray 1.0) color/none)]
        (overlay (conj bomb-colors cursor-color))))))
